Abstract

Background: The injection of water droplets into industrial gas turbines is now commonplace and is central to several proposed advanced cycles. These cycles benefit from the subsequent reduction in compressor work, the increase in turbine work, and (in the case of recuperated cycles) reduction in compressor delivery temperature, which all act to increase the efficiency and power output. An investigation is presented here into the effect such water droplets will have on the operating point and flow characteristics of an aeroderivative gas turbine cycle. Method of Approach: The paper first describes the development of a computer program to study the effects of water injection in multispool industrial gas turbines. The program can operate in two modes: the first uses pre-determined nondimensional wet compressor maps to match the components and is instructive and fast but limited in scope; the second uses the compressor geometries as input and calculates the wet compressor operating conditions as and when required. As a result, it is more computationally demanding, but can cope with a wider range of circumstances. In both cases the compressor characteristics are calculated from a mean-line analysis using suitable loss, deviation and blockage models, coupled with Lagrangian-style droplet evaporation calculations. The program has been applied to a three-spool machine to address issues such as the effects of water injection on power output and overall efficiency, and the off-design nature of the compressor operation. Results: Preliminary results calculated on this basis show similar trends to predictions for single-shaft machines, namely that air mass flow rates and pressure ratios are increased by water injection, and that early stages of the compressor are shifted towards choke and rear stages towards stall. The LP compressor in particular operates at severely off-design conditions. Conclusions: The predicted overall performance of the three-spool machine shows a substantial power boost and a marginal increase in thermal efficiency.

Bassily, A. M., 2001, “Performance Improvements of the Intercooled Reheat Regenerative Gas Turbine Cycles Using Indirect Evaporative Cooling of the Inlet Air and Evaporative Cooling of the Compressor Discharge,” "Proceedings of the Institution of Mechanical Engineers Part A-Journal of Power and Energy", Vol. 215 (A5), pp. 545–557.

Return to: The Effect of Water Injection on Multispool Gas Turbine Behavior

Copyright in the material you requested is held by the American Society of Mechanical Engineers (unless otherwise noted). This email ability is provided as a courtesy, and by using it you agree that you are requesting the material solely for personal, non-commercial use, and that it is subject to the American Society of Mechanical Engineers' Terms of Use. The information provided in order to email this topic will not be used to send unsolicited email, nor will it be furnished to third parties. Please refer to the American Society of Mechanical Engineers' Privacy Policy for further information.

Shibboleth is an access management service that provides single sign-on protected resources.
It replaces the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session.
It operates independently of a user's location or IP address.
If your institution uses Shibboleth authentication, please contact your site administrator to receive your user name and password.